After receiving a tip-off from local people, the 3 Commando Brigade Reconnaissance Force (BRF) uncovered the enemy base in Nahr-e Saraj district.

Inside the compound, which had been laced with IEDs, the BRF found 75 pressure plate devices armed and ready to be laid in the ground to maim and kill. Another 40 were in the process of being constructed and there was a stash of 140 kilograms of homemade explosives which could have been used to make many more.

In what is the BRF’s biggest find to date, they also discovered countless radio transmitters - used to trigger the detonators of IEDs - and more than 30 artillery shells which had been used to attack ISAF patrol bases nearby.

Within the building, there was a second room that was heavily fortified and contained even more deadly equipment.

While some of the items from the outer compound were removed for analysis, due to the risk of booby traps in the inner compound the BRF chose to destroy the whole room - preventing all of the material being used by the insurgents, should they return to salvage the remnants of their stash.

But the victory did not come without a fight. The Royal Marines, soldiers and engineers who make up the BRF stormed the compound, located deep inside the contested Helmand ‘Green Zone’, after reaching the area in two Chinook helicopters.

As the troops prepared to disembark, they came under heavy, sustained fire from all directions. The BRF returned fire and called in support from attack helicopters to take out the insurgent firing points.

We were all unsure what to expect as we left Camp Bastion at short notice. But we knew immediately when we landed we must have stumbled upon something significant. It was pretty intense - one of the biggest contacts we’ve seen this tour.

Members of 3 Commando Brigade Reconnaissance Force inside one of the Chinook helicopters used in the assault in Helmand province [Picture: PO(Phot) Hamish Burke, Crown Copyright/MOD 2011]

As the Chinooks lifted off the ground, one of them was hit by the incoming gunfire. The pilot lifted the helicopter out of the hail of bullets and then made a precautionary landing in an area around a nearby checkpoint.

Soldiers from 4th Battalion The Royal Regiment of Scotland (4 SCOTS) quickly established a security cordon around the aircraft to fully assess the damage. It was later moved back to Camp Bastion to undergo repairs.

Meanwhile, the BRF troops on the ground were engaged in a lengthy fire fight with the enemy, which ended when their snipers tracked and killed an insurgent sharpshooter. This allowed a brief break in the battle for the troops to advance forward towards the suspected weapons cache.

As they got closer, the insurgents who had survived realised they were fighting a losing battle and retreated into the Green Zone.

Sergeant Adam Lesley, one of the team commanders on the operation, said:

This particular operation was a success thanks to the combined efforts of the intelligence experts in Task Force Helmand, the Royal Marines, Royal Engineers, 9/12 Lancers, American C-IED Team and Afghan soldiers involved on the ground.

But it’s also about the intelligence; having the Afghan people on our side helps us get the information we need to carry out operations like this.

Hitting the jackpot is very satisfying, not only because this will be a punishing blow to insurgent capability in this area, but, most importantly for us, it will decrease the amount of IEDs which might harm our friends and colleagues.

It is believed the compound was not only being used as an IED factory, but also as an insurgent school to train up young men to be fighters.

Major Nick Foster Royal Marines, Officer Commanding the BRF during the operation, said:

The loss of such a facility will be a significant blow to the insurgency in the Nahr-e-Saraj district. It was a prized possession for the insurgents and they fought hard to defend it, hitting us with everything they had from the moment the helicopters landed.

Due to the bravery of the Marines, Engineers and Lancers of the BRF, and the skill of the Chinook pilots who landed in the face of heavy fire, we were able to fight our way off the helicopter landing site, and deny the insurgents this IED construction and training site.